Strong, electromagnetic, and weak interactions all cause particle decays.
However, only weak interactions can cause the decay of fundamental particles.

Weak Decays:

Only weak interactions can
change a fundamental particle into another type of particle.
Physicists call particle types "flavors."
The weak interaction can change a charm quark into a strange quark
while emitting a virtual W boson (charm and strange are flavors).
Only the weak interaction (via the W boson) can
change flavor and allow the decay of a truly fundamental particle.

Electromagnetic Decays:

The 0 (neutral pion)
is a
meson. The quark and antiquark can
annihilate; from the annihilation come two photons. This
is an example of an electromagnetic decay.

Strong Decays:

The particle is a meson. It can undergo a strong decay into two gluons (which emerge as
hadrons).